PURPOSE: To control the coating quantity of a coating agent in a coating process of paper or board or an equivalent moving base by a size-press roll.

CONSTITUTION: A coating device includes revolving coating bars (11, 21) revolving on moving bases (4, 5). The coating bars (11, 21) extend across the machine width and are supported on cradles (12, 22) substantially over the entire length. The coating bars (11, 21) spread and smooth a coating agent introduced into the coating devices (10, 20) onto the moving bases (4, 5) before the coating bars (11, 21) in the running directions of the moving bases (4, 5). The coating bars (11, 21) are each a smooth bar of a large diameter and fitted against the moving bases (4, 5) so that the profile of coating quantity of the coating agent can be controlled.